The present invention relates to the treatment of ailments in humans and other mammals, and more particularly, to a method and apparatus for delivering pharmaceutical compounds and genes into live cells of a patient.
It has long been known that it would be desirable to target certain cells within the body with specific pharmaceutical compounds. For example, in the treatment of certain types of cancer with chemotherapy it is necessary to use a high enough dose of a drug to kill the cancer cells without killing an unacceptable high number of normal cells. If the chemotherapy drug could be inserted directly inside the cancer cells, this objective could be achieved. However, some of the best anti-cancer drugs, for example, bleomycin, normally cannot penetrate the membranes of certain cancer cells.
Similarly, certain diseases could be treated by introducing desired genes into the specific cells of the patient. At present, most gene therapy experiments have utilized retroviruses as the carrier of the gene into the cells. When a retrovirus enters a target cell, it integrates essentially randomly in the genome and thus has the potential for introducing mutational damage by the mere fact of its insertion. If the virus integrates adjacent to an oncogene, malignant transformation of the target cell can result.
It is known that genes and other molecules such as pharmacological compounds can be incorporated into live cells through a process known as electroporation. The genes or other molecules are mixed with the live cells in a buffer medium and short pulses of high electric fields are applied. The cell membranes are transiently made porous and the genes or molecules enter the cells. There they can modify the genome of the cell.
The incorporation of drugs into red blood cells via electroporation as well as the incorporation of genes into white blood cells via electroporation have both been demonstrated. The selective incorporation of genes into white blood cells in whole blood via electroporation has also been demonstrated. The electroporation of cells in a flow-through apparatus has also been demonstrated.
Recent methods of gene therapy have used the procedure illustrated in FIG. 1. A substantial amount (e.g. 10%) of a patient's blood is withdrawn and the red and white blood cells are separated over a lengthy time period (e.g. four hours). The red blood cells are then re-infused. A new gene is inserted into the separated white blood cells utilizing a retrovirus. The growth of the white cells is then stimulated before they are re-infused into the patient. The procedure must be repeated every few months and the costs can reach $100,000.00 annually.
It would be desirable to eliminate the need for separating the white cells from the red blood cells. This in turn would eliminate the need to withdraw and re-infuse a portion of the patient's blood. This would make it more convenient and less expensive to perform gene therapy on living patients by genetically modifying their lymphocytes. It would also make it more convenient and less expense to deliver drugs to selected tissues and organs of a living human body by encapsulating them into red blood cells. It would also be desirable to eliminate the need to utilize retroviruses which can result in malignant transformation of the target cells.